PROJECT SUMMARY/ABSTRACT Electrochemical Home Monitoring System for Lithium Blood Level Lithium in the form of lithium carbonate is an important pharmacological treatment option in bipolar disorder (BD) and other conditions. However, lithium has a narrow therapeutic treatment range and its use requires careful monitoring of a patient's lithium blood level, particularly during the initiation of treatment. Current monitoring techniques are inconvenient and costly, requiring a clinical analytical laboratory. There is no commercially-available system for home measurement of blood lithium. The goal of this program is the development of an electrochemically-based detection method packaged into a portable, self-contained, easy-to-use instrument/system for the analysis of lithium. It will be appropriate for use in a home setting for the monitoring of lithium level for BD patients or other patients utilizing lithium treatment. It could also be used in the clinician's office for real-time readings during office visits. A major advantage of the proposed technology is that electrochemical techniques can be packaged into instruments for automated operation in the home which makes them very inexpensive and convenient compared to other laboratory-based analytical techniques. The final home lithium monitor product will have the same ease-of-use of a home glucose monitor and provide the clinician with real- time lithium measurements needed for optimal and cost-effective treatment of the patient. This instrument will reliably and accurately determine the lithium concentration within several minutes after the patient supplies a blood sample by finger prick and the results will be reported in real time to the clinician. Frequent home monitoring could be used both to regulate dosage and to confirm patient is taking the prescribed mediation. This will improve patient care as well as decrease medical costs. During Phase I, Giner, Inc. developed sensor design configurations, with high performance electrode material, and operating conditions which demonstrated feasibility of electrochemical detection of the relevant range (0.2-3 mM) of lithium ion (Li+) in an aqueous medium, including a physiological fluid simulant. The ability to measure lithium ion concentration in the presence of physiological concentrations of sodium and potassium ions was demonstrated and is key to the success of the proposed electroanalytical technique. The ability to measure directly in an aqueous system is an extremely valuable Phase l finding, as it keeps the detection of lithium in blood as simple as possible. The Phase II Specific Aims encompass optimization of the detection method, development of the microanalysis system, design and fabrication of an integrated Instrument, and laboratory sample evaluation in collaboration with The Massachusetts General Hospital Bipolar Clinic and Research Program.